Dry Soil and Arid areas
Some gardens can have problematic dry areas, which might be caused by a number of things, e.g. it is surrounded by buildings/walls and or trees.
Or the soil may be very light and/or sandy.
In such cases treat the soil as sandy soil or take the whole issue out of context and treat the garden as a Mediterranean garden and plant up accordingly.
To do this may create another problem and that is; what to plant in it?
The first thing that could come to mind is Mediterranean plants which in itself might answer the question but then would they contend with the UK weather?
There are a number of drought tolerant plants that will fare reasonably well e.g. Acaena, Achillea, Bergenia, Cotoneaster, Eryngium, Euphorbia, Geraniums, Kniphofia, Lamium, Limonium, Miscanthus, Phormium, Salvia, Sedum, Sempervivum, Stachys, Strelitzia, Verbascum, Vinca and various herbs.
Many of these plants have natural adaptations to help them conserve water such as leaf hairs, succulent or aromatic foliage, and leaves that may be grey, narrow or small.
There are also a number of trees and shrubs that once they have become established will tolerate hot, dry areas e.g. Berberis, Broom, Ceanothus, Cistus, Lavender, Mahonia, Sarcococca, Spartium.
Then there are the spring-flowering bulbs that grow, bloom, and die back before conditions dry out.
You could consider a container garden which would allow you to grow less drought tolerant plants and some less than winter hardy plants providing you can protect the container/s and their contents during frosty periods.
As with all drought-tolerant plants, it is important to ensure they establish well, only then will they be able to find the water they need to survive an arid summer.
Plant in spring or better still, autumn, when conditions are more suitable.
Water the plant in well if the soil is particularly dry, and continue during dry spells until it is growing strongly.
This can take a few years for some trees and shrubs.